rbd: set the 'device' link in sysfs

The rbd driver already provides additional information in sysfs
under /sys/bus/rbd, so we should set the 'device' link in the block
device to reference this information.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

drivers/block/rbd.c

@@ -7143,7 +7143,7 @@ static ssize_t do_rbd_add(struct bus_type *bus,
 	if (rc)
 		goto err_out_image_lock;
 
-	add_disk(rbd_dev->disk);
+	device_add_disk(&rbd_dev->dev, rbd_dev->disk, NULL);
 	/* see rbd_init_disk() */
 	blk_put_queue(rbd_dev->disk->queue);